Superplasticity and grain boundaries in ultrafine-grained materials discusses a number of problems associated with grain boundaries in polycrystals. The role of grain boundaries in processes such as grain boundary diffusion, relaxation and grain growth is investigated. The authors explore the formation and evolution of the microstructure, texture and ensembles of grain boundaries in materials produced by severe plastic deformation. The book is highly beneficial to metallurgists and researchers concerned with the problems of nanomaterials and nanotechnology.